This is an application for continued funding for training in the basic sciences of gene therapy related to cystic fibrosis and other genetic diseases. The training program is based in Penn's Gene Therapy Program(GTP) whose educational mission is to produce exceptional investigators who will become leaders in this field of research. In the past five years, this NIDDK-funded training program had positions for two predoctoral and three postdoctoral fellows, which supported seven predoctoral (including one medical student) and seven postdoctoral trainees. During this period, the graduate training program in gene therapy has flourished and the applicant pool and yield rate for both PhD and combined degree programs has improved substantially; thus support is now requested for three predoctoral and three postdoctoral positions. Predoctoral trainees will be dissertation-level students in the Biomedical Graduate Studies (BGS) program, which is the governing body for biomedical science education at Penn, either as Ph.D. or combined degree students. Most students supported by this training grant will be enrolled in the Cell and Molecular Biology (CAMB) graduate group of BGS, which is home to the Gene Therapy &Vaccines graduate program. Students working on dissertation projects related to gene therapy of genetic diseases in other graduate groups will also be eligible. Postdoctoral trainees will hold either a Ph.D. or M.D./Ph.D., or equivalent degrees and will be trained in basic research in the laboratories of the program faculty. Candidates for all positions will be nominated by individual program faculty members. Nominees will be evaluated and ranked by a committee of the training grant faculty, and the most qualified applicants will be offered support. Throughout the training program, all trainees will attend the GTP seminar series, the CAMB annual retreat, and the trainee seminar series in gene therapy. They will also participate in research seminars and journal clubs relevant to their laboratory's primary research interest. All trainees will be required to take "Molecular Basis of Gene Therapy," a course that was developed by this training program, as well as courses in the ethical conduct of research, care and use of experimental animals, and chemical, biological and radiation safety. Trainees will be supported to attend national meetings to present the results of their work. The training faculty are established researchers with well supported basic science laboratories developing gene therapy for genetic diseases.